Bathtub-Type Spent Catalyst Distributor for FCC Regenerator
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Solution Overview
Problem
Existing spent catalyst distribution methods in regenerators result in uneven distribution, leading to incomplete regeneration, after-burning, temperature increases, and excessive NOx production, which affects the efficiency and reliability of catalyst regeneration.
Innovation Solution
A bathtub-type spent catalyst distributor with an open channel flow using branched distribution troughs, sub-troughs, and downflow tubes to achieve a uniform distribution pattern across the regenerator's cross-sectional area, ensuring even flow and counter-current direction relative to rising combustion gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spent catalyst is distributed using conventional spoked-wheel distributors, then the structure is simple and easy to manufacture, but the catalyst distribution becomes very uneven
Solution Approach 1:
The distributor is segmented into multiple independent trough arms (typically 3-5 arms) radiating from a central collection point. Each trough arm independently distributes catalyst to a specific sector of the regenerator, ensuring uniform radial distribution. This segmentation transforms the single-channel flow into multiple parallel distribution paths, achieving even catalyst spread across the entire regenerator cross-section.
Solution Approach 2:
The distributor design transitions from a two-dimensional spoked-wheel planar structure to a three-dimensional bathtub-type configuration with trough arms having depth and width. The trough arms extend radially outward from the center and distribute catalyst both horizontally across the regenerator width and vertically at different heights, creating a multi-dimensional distribution pattern that ensures uniform catalyst spread throughout the regenerator volume.
2Temperature
If spent catalyst is not uniformly distributed in the regenerator, then the distributor structure remains simple, but after-burning and temperature increase occur in the dilute phase
Solution Approach 1:
By dividing the catalyst distribution into multiple separate trough arms, each serving a specific radial sector, the system ensures that catalyst is evenly distributed across all regions of the regenerator. This prevents localized accumulation of catalyst that would lead to hot spots and after-burning in the dilute phase, as each sector receives a controlled and uniform catalyst load.
Solution Approach 2:
Each trough arm is designed with specific local characteristics including varying depths, widths, and angles optimized for its particular radial position. This local optimization ensures that catalyst flow distribution is tailored to each sector's requirements, achieving uniform catalyst spread throughout the regenerator and preventing localized overheating and after-burning conditions.
3Object-generated harmful factors
If spent catalyst is not uniformly distributed, then the distributor design remains conventional, but NOx is generated in undesirable amounts
Solution Approach 1:
The multi-arm trough distributor segments the catalyst distribution process into multiple controlled channels, ensuring uniform catalyst dispersion across the regenerator. This uniform distribution promotes complete and controlled combustion throughout the dense phase, preventing localized incomplete combustion that would generate excessive NOx in the dilute phase.
Solution Approach 2:
Each trough arm is locally optimized with specific geometric parameters (depth, width, angle) tailored to its radial position, ensuring that catalyst is evenly distributed to all regions. This local quality control achieves uniform combustion conditions throughout the regenerator, eliminating localized zones of incomplete combustion that would produce undesirable NOx emissions.
4Productivity
If spent catalyst is not uniformly distributed, then the distributor structure remains simple, but regeneration efficiency decreases
Solution Approach 1:
The distributor is divided into multiple trough arms that independently distribute catalyst to different radial sectors simultaneously. This parallel segmentation of the distribution function enables uniform catalyst spread across the entire regenerator cross-section, maximizing contact between catalyst and regeneration gases throughout all regions, thereby significantly improving overall regeneration efficiency and productivity.
Solution Approach 2:
The bathtub-type trough arms extend in multiple dimensions (radially outward from center, vertically with depth, and horizontally with width), creating a three-dimensional distribution network. This multi-dimensional approach ensures comprehensive catalyst coverage throughout the regenerator volume, maximizing regeneration efficiency by ensuring all catalyst particles are exposed to regeneration conditions regardless of their position in the regenerator.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures more effective and cleaner regeneration of catalysts, reduces after-burning and NOx production, improves equipment reliability, and prolongs catalyst activity retention while minimizing catalyst makeup costs.
Implementation Method 1
spending catalyst in an open channel flow through a branched distributor which disperses the spent catalyst in a very even distribution pattern
Implementation Method 2
open channel flow through a branched distributor
Implementation Method 3
an open channel flow of fluidized spent catalyst through a branched distributor
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3B
AI summary
An improved spent catalyst regenerator which contains sub-troughs branching off from the main trough, distribution troughs which extend outward from the sides of the main trough and the sub-troughs, and downflow tubes extending downward from the bottom of the main trough and sub-troughs.